1. Field of the Invention
The present invention relates to generally apparatus for recording data or information upon a recording medium and more particularly recording apparatus of the type described and incorporating an analog-to-digital (to be referred to "analog-digital" in this specification) converter.
2. Description of the Prior Art
The recent trend of the recording apparatus is toward the extensive use of computers as disclosed in for instance U.S. Pat. No. 3,936,182. The microcomputers however operate on binary digits "1" and "0" or digitally so that analog electrical signals derived by photo-electric conversion, magneto-electric conversion and thermo-electric conversion for attaining an optimum operation of the recording apparatus must be converted into corresponding digital signals by semiconductor linear integrated circuits and circuits consisting of various combinations of discrete circuit elements such as transistors, resistors, capacitors, inductors and the like, both of which circuits are external to the microcomputer. As a result, the number of electrical elements is in proportion to the number of analog signals to be processed or converted into digital signals so that the principal and fundamental objects of the use of a microcomputer for increasing the packing density, improving the reliability and reducing the cost are adversely affected.
In order to overcome the above and other problems, there has been proposed a method wherein analog-digital converters each in the form of an integrated circuit are combined with the photo-electric, magneto-electric and thermo-electric converters. However these analog-digital converters are of CMOS type and of a sequential-comparison type. Therefore because of the difficulty of integrating a large number of circuit elements at a high packing density and because of a small demand for the analog-digital converters themselves, the cost is still very high. Thus the combination of the photo-electric, magneto-electric and thermo-electric converters with the analog-digital converter will result in complex circuitry and an increase in cost of the recording apparatus.